🕸Fergus Duniho wrote on Mon, Oct 6, 2008 03:00 AM UTC:
Much of today's discussion in this thread has focused on the details
behind a program I do not use. But one of the things that came up in this
discussion is FEN code, which I know something about, since I have
implemented my own version of FEN in Game Courier. Since I'm not sure
what the issues are concerning the use of FEN, I'll make some general
comments about FEN and Game Courier's implementation of it. FEN is used
to represent the positions of pieces on a board. It lists pieces rank by
rank, using numbers for empty spaces. For Chess itself, FEN only needs
letters representing the pieces and numbers to represent empty spaces.
Game Courier uses an advanced form of FEN that makes it useful for
defining the shape of a board, mainly by letting you specify spaces in the
FEN grid that are not part of the board. It also allows the use of longer
piece labels than single letters, and Game Courier allows the use of
aliases, so that a set can use standardized internal names while players
use abbreviations that make sense within the context of the game.
The FEN code provides only limited information about the game. It doesn't
specify how long a rank is (though I could have coded it that way if I had
chosen to), and it doesn't specify the shape of the spaces used. Game
Courier supports squares, two types of hexagons, circular boards, and any
custom board a developer cares to code in positions for. The same sort of
FEN code is used for all of them. Just to give an example, Shogi and Hex
Shogi 81 begin with the same FEN code for the opening position, but they
differ by being played on very different boards. For two games played on
the same board with the same pieces, it would generally be impossible to
tell what the game was by the FEN code alone.
